Process of refining lubricating oils



Patented Jan. 6, 1931 NITED STATE-s A NT" FF E JOHN c. BLACK AND WIRT D. RIAL, or LOS Antennas, CALI ORNIA, ASSIGNORS, 3

mnsnn ASSIGNMENTS," r0 RICHFIEIQD ANGELES, CALIFORNIA,"AI'CORPQRATION OIL oo vrrAnY or CALIFORNIA, or LOS or DELAWARE rnocnssor REEINING LUBRICATILNG oILs Nomr'awing, Application filed April 27,

' This invention relates to an improved processfor refining petroleum oils for the manufactureoflubricating oils. ,This process is particularly adaptable for refining lu'bricatingoil stocks derived from California petroleum, or other oils of like chemicalieomposition, containing a highipercentage of hydrocarbons of the carbocyclic eating oil-stocks derived by distillation of an asphalt, or mixed base crude petroleum oil,

of the required viscosity are treated with sulphuric acid and caustic soda, in quantities sufficient to remove the maj or parto-f said undesirable constituents, but there are still left in the lubricating oil stocks certain small percentages of undesirable constituents, produced by a polymerization and oxidation action during thesaid sulphuric acid treatment whichremain dissolved-in the finished lubricating oil and'cannot be completely removed from all the stock by any known method; whereby the said finished lubricat ing oil will not conform to specifications as required" by the United States Government for turbines, dynamos, and high speed steam engines, these oils being known as class B oils, which are outlined' in the United'States Government specifications, Bureau of Mines Technical Paper 323-A, page 11, test #9.

The test required for this class of oils states that class B oils shall not form a permanent emulsion when agitated with a normal caustic soda solution. y

We have determined that the compounds which cause a lubricating oil stock to emulsify with a solution" of caustic soda are polymerized products,.oxidizedproducts, and oil solublesulfo-compounds. I

l/Ve are aware thata small. percentage of a non-emulsifiable turbine oil. stock may be made from a California or asphalt base 'lu-' 1927. Serial No."187, I10:.

bricating oil by a percolationfiltration ofthe same through Floridafullerls earth, in which ten to twenty percent of the first oil coming through the filter will have non-emulsifying properties to a normal caustic soda solution, but the balance of thestock eighty to ninety percent will not, meet said United States Government specifications required for class B ils V- v These heretofore stated impurities present in Californiaior asphalt base lubricating oil stocks, made by well known methods, not only render to the oil emulsifying properties, but

also render such oil stocks unstable .in color,

whereby asphalt base lubricating oil stocks made by these wellknown methods may when stored for a period oftime turn a darker color and acquire an undesirable blue bloom or fluorescence,which we'believe is due to a continuation, of polymerization promoted by said impurities in the oil. v a

WVe have discovered that these difiiculties can be overcome and a lubricatingoil stock produced which will retain its original color. Our invention consists in "the removal of a part of the above mentioned impurities before the acid treating operation and before any substantialoxidation can take place, while the lubricating oil stocks are being distilled, by .introducing' and commingling immediately therewith a water solution of caustic potash at a pressure and temperature sufficient-to combine with said. impurities, in quantities sufficient to extract therefrom substantially all the oxygen bearing hydrocarbons-"such" as organic acids, aldehydes, andcertain sulphur bearing hydrocarbons such as, hydrogen sulphide, and other unstable sulphur bearing-compounds I unknown in name and chemical composition 1 r and unstable sulphur bearing hydrocarbons f with the formationof sulfo' acids orv sludge,

separating the "acid treated ,oil from the 'sulfo-acids or sludge formed by said acid treatment, then treating said separated oil with a comminuted solid adsorbent agent at temperatures suitable to decompose andadsorb all the soluble and suspended sulfoacids remaining in said acid treated oil,and

producing thereby an oil substantially free of mineral acid, then distilling therefrom the lighter gradesof lubricating oil under s vacuum to separate said lighter gradesiof lubricating" "oil' from the heavier grades or Cylinder stocks, and finally clarifying, puri fying and decolorizing to the. desired degree according to pendingapplication of'John C. Black et al., Serial Number 104,836, filed April 26, 1926.

The following describes the preferred method for carrying out our invention.

Lubricating oil distillate derived from the vacuum distillatiomby any preferred meth- 0d; of a California, Mexican, Texas, or other e asphalt base crude petroleum oil, as it comes from the condenser and after passing 7 through the look-boxhis continuously commingled with approximately 5% by volume of a 10 Beaum caustic potash solution, by passing the same through aehamber filled with bafflle plates, and then into a-tank or agitator provided with an open steam pipe extending to or near the bottom of said agitator,rby means of which said caustic potash solution and lubricating oil distillate are agitated with open steam and at a pressure of approximately pounds gauge, until the temperature is raised to'approximately 280 The mixture of oil andj'caustio potash solution is then permitted torest in quiet without releasing the pressure until the caustic potash containing thedissolved impurities settles to the bottom ofosaid agitater. and isdrawn off. i

The caustic potash treated oil is then washed with, water until substantially free of alkali, cooled and then treated in another agitator with 66 Beaum sulphuric acidat a rate of approximately iO pou'nds of said acid per'barrel of oil charged, after'which most of the sulfo-acid or sludgeformed by said acid treatment is separated from the treated oil. This acid tre'ated oil is then rendered free of mineralacidity by the so called hot contact neutralizing process, as outlined in United States Patent of James W. Weir, Number 1,564,501, wvhich comprises treating alubricating oil stock after treatment with sulphuric acid with acomminuted solid adsorbent, agitating and heat- :ing the mixture to; temperatureranging from 180 to 350 degrees F., and then fsepa- 7 rating the treated lubricating oil stock from the-solid adsorbent and adsorbed "constituents. [The-oil free ofmineral acidity is then subjected to a second distillation under vacuum, whereby the higher grades of lubricating stocks desired are. separated from appended claims.

the heavier grades of lubricating oil, or cylinder stocks.

The saidcylinder stocks remaining in the still may be finished for what is known asclarifying and decolorizing operation employing the process-as outlined in pending application of JohnC. Black 'et 211;, Serial Number 104,836, filed April 26, 1926, which comprises commingling the redistilled' lubricating oil stock with a mixture of an ad 'sorbent clay and an alkaline earth metal compound, such as calcium hydroxide at a temperature of approximately 300Idegrees F, and separating the purified oil'fro'm the alkaline earth metal compound and adsorbent clay containing the emulsifiable constituents o r a V WVhile the process herein described is well adapted for carrying'out the objects of the present invention, it is understood that various modifications may be made without departing from the mvention and the mven- "tion includes all such; modifications and changes as come within the scope of the lVeclaimz' r 1-. That step in the method of treating lubricating oil stocks which consists in treating the" samewith a water solution of caustic potashagitating with steam under a pres- "sure greater than atmospheric, and at a temperatureofapproximately' 280 degrees F., in quantities sufficient to combine with the emulsifying constituents to be separated,

dissolving the combined emulsifying constit- A uentsofthe same therein, and separating the i two liquids." r v 2;"That st'ep in the method of treating lubricating oil. stocks derived from an asphalt base crude petroleum oil,t'which consists in treating the sametwith awater solution of caustic pot-ash agitating withysteam under pressure greater than atmospheric, .and at a temperature ofapproximately 280 de! grees F.', in quantities sufficient to combine with-the emulsifying constituentsto be separated, dissolving the combined emulsifying constituents of the the same therein, and sep- 'arating the two liquids.

3.v Am'ethod of treating lubricating oil stocks, which consists-1n treating the same with a water solution of caustic potash under pressure greater than atmospheric, and at a temperature-of approximately 280 degrees F.,1n quantities sufiicient to combine wlth the "emulsifying constitutents to be separated, dissolving the combined emulsifying constituents of the same therein, and. separating the two liquids, then treating said separated lubricating oil stocks with sulphuric acid in quantitiessufficient to combine with all the unstable hydrocarbons contained therein,

separating the acid treatedv lubricating oil stocks from the unstable hydrocarbons com-- bined with said sulphuric acid, then treating said acid treated lubricating oil stocks with a solid adsorbent material at temperatures greater than 200 F., in quantities'suficient to decompose and adsorb all the sulfo-acidconstituents contained therein which were produced and not separated by said acid treat inent, separating said solid adsorbent material containing the adsorbed. sulfo-acid constituents from the treated lubricating oil stocks,separating the lighter grades of lupetroleum oil, which consists in treating the degrees F., in quantitiessuiiicient to combine same with a water solution of caustic potash under a pressure greater than atmospheric, and at a temperature of approximately 280 degrees F., in quantities sufficient to combine with the emulsifying constituents to be separated, dissolving the combined emulsifying constituents of the same therein, and separating the two liquids, then treating said separated lubricating oil stocks with sulphuric acid in quantities sufficient tocombine with all the unstable hydrocarbons contained therein, separating the acid treated lubricating oil stocks from the unstable hydrocarbons combined with said sulphuric acid, then treating said acid treated lubricating oil stocks with a solid adsorbent material at temperatures greater than 200 F., in quantities sufiicient to adsorb all the sulfo-acid constituents containing therein which were produced and not separated by said acid treat-' ment, separating said solid adsorbent mate oil which will not emulsify when commingled with a water solution of caustic soda, which consists in treating a lubricating oil distillate with a water solution of caustic potash, under a pressure greater than atmospheric and at a temperature of approximately 280 with the emulsifying constituents to be separated, dissolving the'combined emulsifying constituentsof the same therein, and separating the two liquids,then treating said separated lubricating oil stocks with sulphuric acid iii-quantities suficient to combine with substantially all the unstable hydrocarbons contained therein, separating the acid treated lubricating oil stocks from the unstable hydrocarbonscombined with said sulphuric acid, thentreating said} acid treated lubrieating oil stocks with a solid adsorbent material at temperatures greater than 200 F., i

in quantities suflicient toadsorb all the sulfoacid constituents contained therein, which 'were produced andnot separated by said acid treatment,separating said solid adsorbent material containing the adsorbed sulfoacid constituents from the treated lubricating ,oil stocks, separating the lightergradeof lubricating oil stoclrfrom the heavier grade of lubricating oil stock, by a vacuum distillation, and finally clarifying and decolorizing to the required degree, with a decolorizing agent mixed with an alkaline metal hydroxide.-

* '6. The step in the method of improving the color and demulsifying qualities of lubricating oils which comprises heating the lubrieating oils at a temperature of approximately 280 degrees F. with a caustic potash solution under pressure prior to acid treatment thereof. I I

7. The step in the method of improving the color and demulsifyingqualities of lubricating oils which comprises heating the lubrieating oils at a temperature of approximate- :ly 280 degrees F. with a caustic potash solution under pressure prior to acid treatment thereof, allowing the mixture to stratify and washing the oil layer to free it from alkali.

Iii-testimony whereof we affix our signatures.

JOHN C. BLACK. WIRT D. RIAL. 

